s / Drug and Alcohol Dependence 156 (2015) e102–e182 e125 smoking in the early phase of treatment compared with standard care alone. Financial support: NIH R01 DA034537, Joe Young, Sr./Helene Lycaki Funds (State ofMichigan), andDetroitWayneMental Health Authority. http://dx.doi.org/10.1016/j.drugalcdep.2015.07.343 Characterizing vaporizer use among cannabis users Dustin C. Lee2, Benjamin S. Crosier1, A.J. Budney2 1 Center for Technology and Behavioral Health, Dartmouth College, West Windsor, VT, United States 2 Psychiatry, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States Aims: Electronic devices for vaporizing tobacco and cannabis are rapidly emerging and becoming popular among tobacco and cannabis users. The overarching aim of this project is to increase knowledge of the prevalence and phenomenology of vaping cannabis. Understanding the function of vaping (e.g., Is it substituting for smoking cannabis? Is it being combined with nicotine?) across subsets of cannabis users can inform prevention, treatment and policy development. Methods: A 63-item anonymous survey hosted on Qualtrics was distributed through Facebook ads targeting pages focused on interests related to cannabis use. 1,036 volunteers completed the survey and provided valid data. Sample characteristics were as follows: 81%male, 86% Caucasian, mean age 27.3 (SD 11.5) years, 87% and 55% reported over 100 and 1000 days of lifetime cannabis use respectively. Results: Lifetime prevalence of vaping was 72% with 15% reporting vaping as their preferred method of use. Among those that endorsed ever vaping, smoking remained the most common method of current (past 30 days) use for 79%. Only 13% of vaporizer users reported that their rate of smoking cannabis decreased since initiating vaping, suggesting that vaping was not substituting for smoking for themajority of users. Daily smokers weremore likely than occasional smokers to report vaping in the past 30 days [43% vs 20%, p 10 days of opioid misuse in a 28-day (4 week) period; positive or missing samples counted as 5 days of misuse. Results:The153subjects randomized toXR-NTXand155 toTAU did not differ at baseline: 87% reported lifetime heroin use, 73% on probation or parole. Rates of retention on XR-NTX were 61% at 6 months. The relapse event was less common in the XR-NTX arm (43% vs. 64%, p<0.0001; Hazard Ratio 0.48 [95% CI 0.35-0.66]), the median time-to-relapse longer (10.5 vs. 5.0 weeks, p<0.0001), and overall rates of urine samples negative for opioids higher (74% vs. 56%, p<0.0002 [Odds Ratio 2.3 [1.49-3.56]). 5 overdose events (2 fatal) occurred in the TAUarm;nonewere observed amongXR-NTX participants. Conclusions: Six months of XR-NTX opioid relapse prevention therapy among CJS-involved outpatient participants was associated with lower rates of opioid relapse and overall opioid misuse versus treatment-as-usual. ClinicalTrials.gov: NCT00781898. Financial support:NIDA (R01DA024549-55). Studymedication provided in-kind by Alkermes, Inc. http://dx.doi.org/10.1016/j.drugalcdep.2015.07.345